ISDN For Dummies!

By Marie McGuire
March, 1998

Integrated Services Digital Network (ISDN)... those magical letters that have become a part of the telecommunication industry's vocabulary. But what is it? What does it do? What difference does it make? Those questions and more rose in my mind in 1995 when John Morgan of Morgan Comtec told me "ISDN is the way to go. It is the future for telemessaging". I was in the process of upgrading my equipment from paper to paperless and had called Mr. Morgan for information. By the end of our conversation, my mind (and my scratch pad) were full of new terms and ideas. I was comfortable with my hardwire and DID system. I had my reference list of who to call to get what I wanted. I knew how to set up lines and order equipment. I knew when a problem was mine or the phone company's. I knew what I was doing!

After three years of "thinking" ISDN, I can once again say I am comfortable talking with the phone company, knowing exactly what it is I want and getting that service. It doesn't take someone with a degree in engineering or in computer science to understand ISDN You just have to learn to quit thinking in DID and hardwire terms and learn how to speak "ISDN".

Since I was apparently the first answering service in Alabama to utilize ISDN lines, I can assure you that ordering the lines and getting everything coordinated was an experience. 'The first thing you must do is to be sure that your equipment is capable of utilizing the ISDN abilities. Since my system (ANET-II) was built to use ISDN I didn't have to worry about this. Next, be sure that your local telco is able to offer ISDN to your location. Some have a mileage restriction from the central office and if you are outside that area, the charges are normally more than people are willing to pay.

Now, find a telco representative that is familiar with ISDN, I'm sorry, but all those numbers you have accumulated over the years will do you little, if any, good. The normal marketing rep will not have the training to set up a new line, much less a whole new system. This is not to say they won't try their best, but to save you and the reps a lot of headaches and troubles, find one that you are comfortable talking to and who does not say "huh" when you starts peaking of BRI, DOEs, NTIs and buttons.

Speaking of BRI, DOEs, NTIs and buttons -- what are they? BRI (Basic Rate Interface) is a type of line that includes three channels; two Bearer (B) channels plus one Data (D) channel, which is called a 2B plus D. O.K., so what? The analog lines are capable of doing one thing at a time, while ISDN lines are able to do multi-functions at the same time. The B channels can handle the voice transmissions faxing, modems, etc. while the D channel handles the monitoring of the line. Since the D channel is always open, this provides the possibility of performing all sorts of operations (security systems, fire and emergency monitoring, etc). Also, the D channel allows "conversation" between you and the telco's central office, (i.e. letting you know that another call is coming in, you can tell the central office to patch or transfer two calls, you can know why you are getting the call, etc.). We use one BRI ISDN line for each pair of operator workstation s since the line will support two voice channels.

Although the majority of our accounts forward their calls to us, we also have some accounts set up as DOEs. The simple way to understand DOEs would be to consider them as your hardwire accounts. Actually the acronym DOE just stands for "Digital Office Equipment".

Figure that one out. These accounts do not call forward. The line can be bridged by either TAS or the client. There is an actual connection of an accounts line to your ISDN equipment . Imagine a large phone with 64 push buttons. Each of those buttons can represent one DOE. When ordering these lines, you no longer tell the rep what jack and position you want the line on, instead you tell them what button to put the line on.

The NTI is a network terminator. This is the bridge between the telco and your equipment. These can be purchased from a variety of vendors with prices varying widely, shop around. You need one NTI for each BRI-ISDN line coming into your office. This piece of equipment is priceless when a line is down. If a DID trunk is down for some reason, you may not be aware of it for quite a while. If an ISDN line Is down (which rarely happens), the NTI will alert you of a failure. This also is great when tracking a problem and the phone company insists it is your equipment for this monitors the line coming into your site. After all this, perhaps you've decided that maybe it just isn't worth the hassle. Refer to the comparison chart (previous page) between DID and ISDN.

Pricing of ISDN lines is normally less expensive than DID trunks. Check with your telco regarding rates for installation and monthly charges. Normal activities can be done in less time with ISDN. Line connections are made and disconnected faster. Patches (transfers) are actually done at the telco central office therefore, your equipment is not tied up and your customers don't complain of busy signals due to patches. You need less lines because ISDN lines all handle multiple calls at one time, while DIDs can only handle one at a time.

While the merits of ISDN are many, and I'm sure in the future the capabilities will continue to grow, each person must determine if the benefits are worth the change. In my case, I can certainly say, YES.

Marie McGuire, is the General Manager of AnswerTel, and has been with AnswerTel since 1983. She is a member of ATSI and installed the first 'known' ISDN system to operate in a telemessaging environment; Morgan Comtec's A-NET II. Marie can be reached at 205-230-9404

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